CVDD Window Thermal Transport for Semiconductor Hot-Spots
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Solution Overview
Problem
Semiconductor dies in multi-board assemblies face challenges in heat removal due to the inability to place metallic fins directly over the die, and existing Chemical Vapor Deposition Diamond (CVDD) sheets are expensive and not widely adopted for thermal management.
Innovation Solution
A board assembly is created with a CVDD window and a layer of thermally conductive paste positioned directly over hot-spots on the semiconductor die, where the CVDD window has a footprint less than 20% of the die's footprint, allowing for effective thermal conductivity without the high cost of extensive CVDD material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If metallic fins are used for thermal transport, then heat removal is effective, but they cannot be placed directly over die in multi-board assemblies
Solution Approach 1:
The patent introduces CVDD windows as an intermediary thermal transport mechanism between the die and the cooling system. These diamond windows are placed directly over hot-spots on the die surface, acting as a mediator that conducts heat away from the die in multi-board assemblies where traditional metallic fins cannot be used.
Solution Approach 2:
The patent applies thermal transport materials selectively at specific locations rather than uniformly across the entire die surface. CVDD windows are positioned only over identified hot-spot areas, providing localized thermal management where it is most needed while reducing overall material usage.
2Temperature
If CVDD sheets are used for thermal conveyance, then thermal conductivity is high, but the expense is prohibitive for widespread adoption
Solution Approach 1:
The patent reduces cost by applying CVDD material only where thermal management is critical - specifically over hot-spot areas on the die surface. This localized application maintains effective thermal conductivity where needed while dramatically reducing the quantity of expensive CVDD material required compared to full-die coverage.
Solution Approach 2:
The patent uses partial coverage of CVDD windows over the die surface rather than complete coverage. By applying the high-performance material only to the extent necessary for effective thermal management of hot-spots, the solution achieves sufficient thermal conductivity without the prohibitive cost of full-area application.
3Ease of manufacture
If CVDD windows with small footprint are used, then material cost is reduced, but thermal transport capability must be maintained
Solution Approach 1:
The patent strategically positions small-footprint CVDD windows directly over hot-spot locations on the die surface. This localized placement ensures that the limited CVDD material provides maximum thermal transport benefit by concentrating it where heat generation is highest, maintaining effective thermal capability with minimal material.
Solution Approach 2:
The patent employs partial coverage of the die surface with CVDD windows, using only the minimum area necessary to achieve effective thermal management. The windows are sized and positioned to cover hot-spot regions adequately without excessive material usage, balancing cost reduction with thermal performance requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively removes heat from semiconductor dies by leveraging the high thermal conductivity of CVDD windows, positioned under hot-spots, while minimizing material costs by using only a fraction of the expensive CVDD material needed for full die coverage.
Implementation Method 1
Chemical Vapor Deposition Diamond (CVDD) has a very high thermal conductivity and can be formed in thin sheets
Implementation Method 2
a layer of thermally conductive paste in direct contact with a first surface of the CVDD window along the full extent of the first surface of the CVDD window and in direct contact with the semiconductor die
Data Source
AI summary
A method for forming a board assembly includes identifying a location of a hot-spot on a semiconductor die and cutting an opening in a circuit board corresponding to the location of the identified hot-spot. A Chemical Vapor Deposition Diamond (CVDD) window is inserted into the opening. A layer of thermally conductive paste is applied over the CVDD window. The semiconductor die is placed over the layer of thermally conductive paste such that the CVDD window underlies the hot-spot and such that a surface of the semiconductor die is in direct contact with the layer of thermally conductive paste.